Midwinter Bald Eagle Survey

By Jean Flick  

                                             

On a cold day in January, a group of hearty individuals, led by Paul Balkenbush, Hagerman National Wildlife Refuge Deputy Manager, searched the Texas side of Lake Texoma for the presence of bald eagles.  HNWR has supported the Midwinter Bald Eagle Survey for a number of years, providing bald eagle counts that are used to estimate trends of wintering bald eagle populations across the lower 48 states.

Each January, several hundred individuals count eagles along standard, non-overlapping survey routes as part of this nationwide survey.  Started in 1979, counts were first coordinated by the National Wildlife Federation and are now coordinated by the U.S. Army Corps of Engineers (USACE). 

Paul Balkenbush coordinates this effort for the Texas portion of Lake Texoma.  The 2018 survey was completed in one day in January, by individuals who were each assigned portions of the shoreline area between Highway 69/75 and I-35.  Team members may travel by boat or vehicle to search for eagles, with most choosing to travel by vehicle.  This year, the team completed 859 minutes of survey time with 67.3 miles of shoreline observed.  Bald eagle sightings included 4 adult and 8 immature eagles.

Paul reports the team’s data, including the time spent and miles observed.  This data, including the number of eagles/shoreline mile and number of eagles/survey hour is compiled from regions across the country and can then be used to support bald eagle relative density estimates.

The USACE website provides summary trend tables from 1986-2010, which show an overall increasing trend in eagle sightings in the majority of national regions (6 of 9 regions) but an overall decreasing trend in sightings in Texas during that same time period.  A wide range of variables may impact this data.

The USFWS considers the recovery of bald and golden eagles to be a conservation success story.  When the bald eagle was adopted as our national symbol in 1782, the country may have had as many as 100,000 nesting eagles.  By 1963, with only 487 nesting pairs of bald eagles remaining, the species was in danger of extinction. Loss of habitat, shooting, and DDT poisoning contributed to the near demise of our national symbol.

The Endangered Species Act was enacted in 1973, and in 1978 the bald eagle was listed as endangered throughout much of the contiguous U.S.  Habitat protection afforded by the Endangered Species Act, the federal government’s banning of DDT, and conservation actions taken by the American public have helped bald eagles make a remarkable recovery.  Bald eagles were removed from the endangered species list in August 2007 because their populations recovered sufficiently.  (USFWS Endangered Species website and Fact Sheets)

Data from a variety of sources, including estimates from the annual Midwinter Survey, contribute to our body of knowledge regarding the continued successful recovery of bald eagle populations.  Paul is always looking for members to join the Bald Eagle Survey team.  Participation is open to any interested birder who wants to spend a day looking for eagles along the lakeshore.  Contact Paul at the refuge office if you would like to participate on the team in January 2019.

Photo Credit:  Bald Eagle at HNWR by Brian Fant